Illicit Discharge Detection and Elimination

The term “illicit discharge” is defined in EPA’s Phase II storm water regulations as “any discharge to a municipal separate storm sewer that is not composed entirely of storm water, except discharges pursuant to an NPDES permit and discharges resulting from fire-fighting activities.”

Illicit discharges can be categorized as either direct or indirect.

Examples of direct illicit discharges:

  • sanitary wastewater piping that is directly connected from a building to the storm sewer
  • materials (e.g., used motor oil) that have been dumped illegally into a stormdrain catch basin
  • a shop floor drain that is connected to the storm sewer
  • a cross-connection between the municipal sanitary sewer and storm sewer systems

Examples of indirect illicit discharges:

  • an old and damaged sanitary sewer line that is leaking fluids into a cracked storm sewer line
  • a failing septic system that is leaking into a cracked storm sewer line or causing surface discharge into the storm sewer

The Town of Bel Air is in the process of developing a comprehensive IDDE program beginning with the enactment of an Illicit Discharge and Connection ordinance passed by the Board of Town Commissioners on June 2, 2014.


If you observe any circumstance occurring in Town that you feel may be detrimental to the environment, please do not hesitate to call the Department of Public Works at 410-638-4536.

Storm water Pollution & Illicit Discharges
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